High Fat Diet Affects Reproductive Functions in Female Diet‐Induced Obese and Dietary Resistant Rats

Abstract

BACKGROUND Incidence of ovulatory disorders is common in obese animal models. The mechanism behind this effect is not clear. We hypothesized that high fat (HF) diet induces alterations in neuroendocrine mechanisms resulting in anovulation in diet-induced obese (DIO) animals. METHODS Adult female DIO and diet-resistant (DR) rats were fed either chow or HF diet (45% calories from fat) for 6 weeks. Oestrous cyclicity and body weight were monitored regularly. At the end of treatment, rats were implanted with a jugular catheter to monitor luteinising hormone (LH) levels on the day of prooestrous. Rats were sacrificed on the following prooestrous, their brains and ovaries were collected. Plasma from trunk blood was analyzed for oestradiol and leptin concentrations. Ovaries were fixed and sectioned for histological analysis. Brains were removed, frozen and sectioned and norepinephrine (NE) concentrations in discrete hypothalamic areas were measured using HPLC-EC. RESULTS HF diet affected oestrous cyclicity in both DIO and DR rats with the effect being more pronounced in DIO animals. HF diet increased leptin levels in both DIO and DR rats. Oestradiol levels were low in the DIO-HF group. NE levels in the hypothalamus were unaffected by HF diet or genotype. A normal LH surge was observed in DR-Chow rats and LH levels were low in the rest of the groups. CONCLUSION DIO rats have an inherently reduced reproductive capacity and exposure to a HF diet decreases it further. A reduction in oestradiol and LH surge levels could contribute to this effect, however the underlying mechanisms need to be studied further.

Study of failures in a rabbit line selected for growth rate

“…On the other hand, it has been suggested that an increase in serum leptin concentration may have a role in the steroidogenesis of pre-and post-ovulatory follicles: leptin suppresses estradiol production and interferes with the development of dominant follicles and oocyte maturation (Moschas et al, 2002). Thus, the absence of ovulation observed in non-ovulated mated females may be related to leptin concentrations, in accordance with other authors that showed how an elevation in leptin levels is likely to cause a reduction in secretion by decreasing LH production by the pituitary, also preventing the release of the oocytes from the preovulatory follicles (Duggal et al, 2000;Brecchia et al, 2006;Balasubramanian et al, 2012). Our results also showed an increase in BOHB in non-ovulated females.…”

“…Therefore, these results suggest that problems due to LH secretion or to LH follicular receptors can be discarded. Moreover, Balasubramanian et al (2012) showed that lower LH levels impair ovulation process, causing a lower number of fresh corpora lutea, as we detected in this work.…”

“…Additionally, high weight and diet could suppress reproductive functions by acting directly on the pituitary or the ovary (Balasubramanian et al, 2012). Excessive lipid storage in mice was shown to induce ovarian dysfunction disorders with advanced follicular atresia, apoptosis and defective steroidogenesis (Seke et al, 2012).…”

Maternal high-fat diet induces insulin resistance and deterioration of pancreatic β-cell function in adult offspring with sex differences in mice

“…The reason for the reduction in plasma estradiol levels is not clear. However, Balasubramanian et al (2) reported that HFD exposure increases serum leptin levels in the DIO group and that elevated leptin levels can impair ovulation and cause a reduction in estradiol synthesis in the ovary, resulting in inversely decreased estradiol levels. Further studies are needed to prove that HFD-induced increase in leptin levels is responsible for the decrease in estradiol levels.…”

Influence of a High-Fat Diet on Cardiac iNOS in Female Rats

“…Balasubramanian et al reported that a 6-week HF diet, where 45% of calories came from fat, reduced the concentration of oestradiol in female rats [67].…”